Component feeding is a well-known process in Surface Mounting Technology (SMT). In general, a feeder is used to sequentially supply surface mountable electrical components to a pickup location for subsequent placing, by a pick-and-place machine, onto a printed circuit board (PCB) which is pre-printed with solder paste.
One form of feeder is a tape and reel feeder in which the electrical components are packaged on a tape that is wound onto a reel. The tape comprises individual pockets each containing one of the electrical components that are individually sealed in the pockets by a covering of thin film. In use, the film is removed when the tape enters the pickup location therefore leaving a pocket containing one of the electrical components in a position accessible by the pick-and-place machine. Unfortunately, the tape is substantially wider than the components located in the pockets that increases the width of the feeder. Further, the reel and apparatus for removing the film also add to the width and overall size of the feeder.
Hopper feeders also known as bulk or tube feeders are an alternative to tape and reel feeders. Hopper feeders comprise a hopper in communication, along a downwardly sloping passage, with the pickup location. The downwardly sloping passage makes use of gravity for supplying the components to the pickup location. To further assist the supplying of the components to the pickup location a combination of gravity and air blasting has also been used.
The pickup location has an abutment wall and an aperture. The abutment wall abuts the components supplied from the hopper before they are removed, through the aperture, by the pick-and-place machine. The supply of components to the pickup location must be controlled, otherwise undesirable amounts of friction between the abutment wall and an abutting component can result. This friction is due to a mass of stacked components in the downwardly sloping passage pushing the abutting components into the abutment wall. Accordingly, this friction may cause problems when the pick-and-place machine attempts to remove the abutting component. Further, unnecessary friction between the abutting component and an adjacent component can further hinder the removal of the abutting component.
In order to reduce the friction described above, the supply of components to the pickup location is mechanically controlled to separate components in the downwardly sloping passage from a component in the pickup location. For example, one conventional approach is to use a pneumatically controlled slotted disk located horizontally in series between the pickup location and sloping passage. The slotted disk has two diametrically opposite slots for sequentially engaging a component. The disk rotates through 180 degrees in a timed sequence to thereby transport an individual component, engaged in one of the slots, from the passage to the pickup location.
The above conventional mechanically controlled component separation approach requires valuable limited space. This is primarily due to the disk being substantially larger than the components and for practical reasons it is located horizontally therefore increasing the width of the feeder. In order to overcome this disadvantage, PCT/US97/04856 describes a feeder having an upwardly inclined portion which is upwardly inclined towards pick up location. This therefore reduces friction between the abutment wall and abutting components due to a mass of stacked components. However, there is still a need to reduce this friction further to allow ease of removal the abutting component.